Ongoing work for adding per-thread UTCB structures.

Added setting of utcb address to l4_thread_control.
This is going to be moved to exchange_registers() since we need to pass
both the utcb physical and virtual address and exregs fits such context
modification better than thread_control.

tasks/mm0/src/init.c

@@ -18,6 +18,7 @@
 #include <test.h>
 #include <boot.h>
 
+
 /* A separate list than the generic file list that keeps just the boot files */
 LIST_HEAD(boot_file_list);
 

tasks/mm0/src/utcb.c

@@ -0,0 +1,27 @@
+/*
+ * Management of task utcb regions and own utcb.
+ *
+ * Copyright (C) 2007-2009 Bahadir Bilgehan Balban
+ */
+
+#include <l4lib/arch/utcb.h>
+#include <l4/macros.h>
+
+/*
+ * UTCB management in Codezero:
+ *
+ * 1.) Every task in the system defines an array of utcbs in a special .utcb
+ *     section that is page-aligned and to be kept wired in by the pager.
+ * 2.) The region marks are written to bootdesc structure at compile-time.
+ * 3.) Pager reads the bootdesc struct from the microkernel during init.
+ * 4.) Pager initialises structures to alloc/dealloc new utcbs for every address
+ *     space.
+ * 5.) Pagers dynamically allocate utcb addresses as each thread is created
+ *     via a thread_control() system call.
+ * 6.) Each thread in an address space learns their utcb address from a
+ *     well-defined KIP offset. This is updated as each thread becomes runnable.
+ */
+
+
+
+